Comment on attachment 769224[details][diff][review]
Patch v1.
Requesting approval to land on try, oak, and m-i.
[Security approval request comment]
How easily could an exploit be constructed based on the patch?
A crash easily, I'm not sure how easy it is to execute something elevated.
Do comments in the patch, the check-in comment, or tests included in the patch paint a bulls-eye on the security problem?
No comments, but the content of the patch seems somewhat obvious what it's fixing.
Which older supported branches are affected by this flaw?
All for at least 10 versions.
If not all supported branches, which bug introduced the flaw?
bug 307181 (background updates)
Do you have backports for the affected branches? If not, how different, hard to create, and risky will they be?
Should be the same patch everywhere.
How likely is this patch to cause regressions; how much testing does it need?
Not likely after I test on oak.

Comment on attachment 769224[details][diff][review]
Patch v1.
sec-approval+ for trunk. We should get this on branches well before the next release given the amount of security issues in this area recently.

Comment on attachment 769224[details][diff][review]
Patch v1.
[Approval Request Comment]
If this is not a sec:{high,crit} bug, please state case for ESR consideration:
User impact if declined:
It is a sec:high
A process that already has local access could potentially get elevated access.
Buffer overflow, someone could write into process memory and possibly cause it to jump to execute their own code
Bug caused by (feature/regressing bug #):
bug 307181
Fix Landed on Version:
mozilla25
Risk to taking this patch (and alternatives if risky):
Low
String or UUID changes made by this patch:
None
See https://wiki.mozilla.org/Release_Management/ESR_Landing_Process for more info.